This invention relates generally to displaying lightning strikes.
Electrical storms pose a host of problems for aircraft pilots. For example, lightning can wreak havoc on in-flight electronics and instrumentation. Of greater concern, however, is the air turbulence that always accompanies electrical storms. The strength of this turbulence makes it dangerous for aircraft, particularly small aircraft, to fly through electrical storms.
Equipment therefore has been developed which enables pilots to detect, and thus avoid, electrical storms during flight. This equipment typically includes a detector for detecting electrical activity of nearby storms, and a monitor for displaying lightning strikes (meaning any electrical discharge) occurring in these so-called storm cells. Current lightning strikes are depicted on the monitor as an xe2x80x9cxxe2x80x9d or a xe2x80x9c+xe2x80x9d, which remains displayed for an amount of time, after which the xe2x80x9cxxe2x80x9d or xe2x80x9c+xe2x80x9d is removed.
Lightning displays, such as those described above, make it difficult for pilots to interpret the information that they are receiving. For example, it is difficult to determine the spatial density of lightning in a particular area using such a display. It is also difficult to determine storm trend information, such as whether a storm is increasing or decreasing in intensity.
The invention displays lightning strikes as uniformly-structured (e.g., gaussian) kernels that decay over time. For one example of decay, the kernels may decrease in size over time, in order to indicate how long ago lightning strikes occurred in an area.
Preferably, each kernel is a circular area that can be conceptualized as a standard gaussian surface of rotation. A visible feature, such as intensity, of each pixel in the circular area corresponds to the height of a corresponding point on the gaussian surface. In addition to gaussians, surfaces of rotation for any (convex) contours, such as cones, may be used to conceptualize the kernels. overlapping areas of the kernels are displayed in different colors than corresponding non-overlapping areas of those kernels. The colors may differ in terms of hue, intensity and/or saturation, in any combination. For example, a non-overlapping area may be displayed as yellow, and a corresponding overlapping area displayed as red to indicate a relatively higher density of lightning.
The color of an overlapping area is a function of the number of kernels that overlap in that area, of the center positions of displayed kernels, and of the elapsed time since each kernel was first displayed. For example, if several kernels overlap, the overlapping area-may be displayed as red to indicate a high density of lightning and, if several more kernels overlap, the overlapping area may be displayed as magenta to indicate an even higher density of lightning in that area.
Thus, in a given area, the kernels vary in size and color based on the number of lightning strikes in that area and the time that those strikes occurred. The display therefore provides pilots with a clear picture of lightning density and storm trends in the given area.
Lightning strikes may be displayed as they are detected (in real-time) or they may be stored for later display. Thus, the history of a storm may be recorded and stored for later playback. The pilot is given control over how this history information is displayed. For example, the pilot can display the strikes as gaussian kernels or even as discrete symbols (e.g., xe2x80x9cx""sxe2x80x9d), if desired. Likewise, the pilot can alter the rate at which recorded history information is displayed, and thereby view lightning information in a historical context.
According to one aspect, the invention displays a lightning strike as a uniformly-structured kernel that decays over time. This aspect of the invention may also include one or more of the following features/functions.
The uniformly-structured kernel comprises a gaussian kernel. The lightning strike is detected, its location is determined, and the lightning strike is displayed based on the detected location. The location of an aircraft may be displayed relative to the lightning strike. Decay of the kernel may be depicted as a decrease in size and/or amplitude of the gaussian kernel over time.
Two or more lightning strikes may be displayed as uniformly-structured kernels that decay over time. Areas of kernels for these lightning strikes that overlap may be displayed in one or more different colors than corresponding non-overlapping areas of kernels for the two or more lightning strikes. A color of an overlapping area is a function of a number of kernels that overlap in that area.
According to another aspect, the invention displays lightning strikes by storing information relating to a lightning strike and retrieving the information. The lightning strike is displayed, based on the information, as a uniformly-structured kernel that decays over time. This aspect of the invention may also include one or more of the following features/functions.
The lightning strike is detected and its location is determined. The information relating to the lightning strike may include the location of the lighting strike and/or a time that the lightning strike occurred. The information may include a record of lightning strikes that occurred over a period of time, where each lightning strike corresponds to a uniformly-structured kernel that decays over time. The rate at which the record of lightning strikes is displayed may be controlled. A current location of an aircraft relative to the lightning strike may be displayed by determining the current location relative to the lightning strike, and displaying the current location. A warning is displayed regarding current lightning strikes while the retrieved lightning strike information is being displayed.
According to still another aspect of the invention, lightning strikes are displayed by assigning uniformly-structured kernels to lightning strikes. The uniformly-structured kernels comprise pixel matrices in which pixels at centers of the matrices have greater values than pixels at edges of the matrices. An overlapping portion of two or more uniformly-structured kernels is displayed by summing pixel values in the matrices of the two or more uniformly-structured kernels at the overlapping portion.
This aspect of the invention may include one or more of the following. Pixel values in the pixel matrices correspond to colors on a color continuum. Pixels values in the pixel matrices are reduced by an amount at set time periods until the pixel matrices have zero values.
According to still another aspect, the invention displays two or more lightning strikes as uniformly-structured kernels, where portions of two or more of the uniformly-structured kernels overlap in an area. A color of the area is a function of a number of uniformly-structured kernels that overlap in the area.
In this aspect, additional lightning strikes may be displayed as uniformly-structured kernels, where portions of one or more of the uniformly-structured kernels overlap in the area. The color of the area increases in amplitude based on the number of uniformly-structured kernels that overlap the area. The color of the area may be one or more of a continuum of colors ranging from magenta at a high color amplitude to black at a low color amplitude.
According to still another aspect, the invention displays lightning strikes, in response to a user input, as either (i) uniformly-structured kernels that decay over time, or (ii) as discrete symbols.
According to still another aspect, the invention displays a bearing line for navigating around lightning strikes. Lightning strikes are displayed on a display screen, and a bearing line is also displayed on the display screen relative to the lightning strikes. The lightning strikes may be displayed as uniformly-structured kernels that decay over time, or as discrete symbols, and the bearing line may be movable relative to the strikes.
Other advantages and features will become apparent from the following description and the claims.